Beta beam scenarios … for neutrino oscillation physics

Beta beam scenariosBeta beam scenarios… for neutrino oscillation physics… for neutrino oscillation physics

Beta beam meetingBeta beam meetingAachen, GermanyAachen, Germany

October 31-November 1, 2007October 31-November 1, 2007

Walter WinterWalter WinterUniversität WürzburgUniversität Würzburg

November 1, 2007 Aachen 07 - Walter Winter 2

ContentsContents Introduction: Introduction:

Neutrino oscillation physics with beta beamsNeutrino oscillation physics with beta beams Beta beam scenariosBeta beam scenarios Optimization of a green-field scenarioOptimization of a green-field scenario Using different isotopesUsing different isotopes Physics case for a beta beam?Physics case for a beta beam? SummarySummary


Neutrino oscillations with two flavorsNeutrino oscillations with two flavorsMixing and mass squared difference:Mixing and mass squared difference:

“disappearance”: “disappearance”:

“appearance”: “appearance”:

Amplitude~Frequency

Baseline: Source - Detector

Energy


Picture of three-flavor oscillationsPicture of three-flavor oscillations

Magnitude of Magnitude of 1313 is key tois key to

““subleading” effects: subleading” effects: Mass hierarchy Mass hierarchy

determinationdetermination CP violationCP violation

Use Use ee transitions on atmospheric oscillation scale transitions on atmospheric oscillation scale

(“Oscillation maximum”)(“Oscillation maximum”)

Coupling strength: 13

Atmosphericoscillation:Amplitude: 23

Frequency: m312

Solaroscillation:Amplitude: 12

Frequency: m212

Sub-leading

effect: CP


Matter effects in Matter effects in -oscillations (MSW)-oscillations (MSW) Ordinary matter Ordinary matter

contains electrons, contains electrons, but no but no ,,

Coherent forward Coherent forward scattering in matter scattering in matter has net effect on electron flavor because of CC (rel. phase shift)has net effect on electron flavor because of CC (rel. phase shift)

Matter effects proportional to electron density and Matter effects proportional to electron density and baselinebaseline Hamiltonian in matter:Hamiltonian in matter:

Y: electron fraction ~ 0.5

(electrons per nucleon)

(Wolfenstein, 1978; Mikheyev, Smirnov, 1985)

Matter potential not CP-/CPT-invariant!


Appearance channels: Appearance channels: ee

Complicated, but all interesting information there: Complicated, but all interesting information there: 1313, , CPCP, mass hierarchy (via A), mass hierarchy (via A)

(see e.g. Akhmedov, Johansson, Lindner, Ohlsson, Schwetz, 2004)

Anti-nus


The role of neutrinos+antineutrinosThe role of neutrinos+antineutrinos CP asymmetryCP asymmetry

(vacuum)(vacuum)suggests the usesuggests the useof neutrinos andof neutrinos andantineutrinosantineutrinos

One discrete deg.One discrete deg.remains in remains in ((1313,,)-plane)-plane

Best-fit

-beam,

-beam, anti-


Often used performance indicatorsOften used performance indicators Future experiment performance depends on (simulated) Future experiment performance depends on (simulated)

values implemented by naturevalues implemented by nature Often shown: Often shown: Discovery reachesDiscovery reaches ( (1313, ,

MH, CPV) as a function of these MH, CPV) as a function of these simulated values; mainly as a function simulated values; mainly as a function of of 1313 and and CPCP

Sensitivity to Sensitivity to 1313: Largest value of : Largest value of 1313, which cannot be , which cannot be distinguished from a simulated distinguished from a simulated 1313=0=0 Corresponds to new Corresponds to new exclusion limitexclusion limit if no signal if no signal Marginalization over Marginalization over 1313, , CPCP, mass hierarchy, mass hierarchy Does not depend on simulated Does not depend on simulated CPCP


Correlations and degeneraciesCorrelations and degeneracies Connected (green) or disconnected (yellow) degenerate Connected (green) or disconnected (yellow) degenerate

solutions (at a chosen CL) in parameter spacesolutions (at a chosen CL) in parameter space Discrete degeneracies – even if Discrete degeneracies – even if s+anti-s+anti-s: s: (Barger, Marfatia, Whisnant, (Barger, Marfatia, Whisnant,

2001)2001) Intrinsic (Intrinsic (,,1313)-degeneracy )-degeneracy (Burguet-Castell et al, 2001)(Burguet-Castell et al, 2001)

sgn-degeneracy sgn-degeneracy (Minakata, Nunokawa, 2001)(Minakata, Nunokawa, 2001)

((2323,,/2-/2-2323)-degeneracy )-degeneracy (Fogli, Lisi, 1996)(Fogli, Lisi, 1996)

Affect performance of appearance Affect performance of appearance measurements. For example, measurements. For example, 1313 sensitivity: sensitivity:

(Huber, Lindner, Winter, 2002; Huber, Lindner, Rolinec, Winter, 2006)(Huber, Lindner, Winter, 2002; Huber, Lindner, Rolinec, Winter, 2006)


Example for degeneracy resolution:Example for degeneracy resolution: “Magic baseline”“Magic baseline”

Idea:Idea:Yellow term = 0Yellow term = 0 independent independent of E, oscillation parametersof E, oscillation parameters

Purpose: Purpose: “Clean” measurement of “Clean” measurement of 1313 and mass hierarchy and mass hierarchy

Drawback: No Drawback: No CPCP measurement at magic baseline measurement at magic baseline combine with shorter baselinecombine with shorter baseline

(Huber, Winter, 2003)


Beta beam at very long baselineBeta beam at very long baseline Operate a beta beam at the magic baseline?Operate a beta beam at the magic baseline?

(Agarwalla, Choubey, Raychaudhuri, 2006)(Agarwalla, Choubey, Raychaudhuri, 2006)

Use magnetized iron calorimeter as detectorUse magnetized iron calorimeter as detectorCERN-ICAL (INO) ~ magic baseline CERN-ICAL (INO) ~ magic baseline

Authors use Authors use 88B and B and 88Li with rel. moderate Li with rel. moderate ~ 250 - 500 ~ 250 - 500L~ 7000 – 9000 km bands

Beta beam scenariosBeta beam scenarios


Motivation: Experiment classesMotivation: Experiment classesSourceSource Production … and DetectionProduction … and Detection LimitationsLimitations LL <E><E>

ReactorReactor SystematicsSystematics 1-2 km1-2 km ~4 MeV~4 MeV

Super-Super-beambeam

Intrinsic Intrinsic beam BGbeam BG,,systematicssystematics

100-100-2,500 km2,500 km

0.5 – 5 0.5 – 5 GeVGeV

Neutrino Neutrino factoryfactory

Charge Charge identificationidentification,,NC BGNC BG

700-700-7,500 km7,500 km

5-50 5-50 GeVGeV

-beam-beam SourceSourceluminosity?luminosity?

100-100-2,000 km2,000 km

0.3 – 10 0.3 – 10 GeV GeV

For leading atm. params Signal prop. sin2213 Contamination


Original beta beam conceptOriginal beta beam concept

Key figure (any beta beam):Key figure (any beta beam):Useful ion decays/year?Useful ion decays/year?

Often used “standard values”:Often used “standard values”:3 103 101818 66He decays/yearHe decays/year1 101 101818 1818Ne decays/yearNe decays/year

Typical Typical ~ 100 – 150 ~ 100 – 150 (for CERN SPS) (for CERN SPS)

eFeNe 189

1810

eLiHe 63

62

(CERN layout; Bouchez, Lindroos, Mezzetto, 2003; Lindroos, 2003; Mezzetto, 2003; Autin et al, 2003)

Compared to superbeam: no intrinsic beam backgroundCompared to superbeam: no intrinsic beam background Compared to neutrino factory: no charge identification requiredCompared to neutrino factory: no charge identification required In principle, very interesting alternative concept!In principle, very interesting alternative concept!

(Zucchelli, 2002)


Higher Higher beta beam beta beam

16

Beta beam scenarios: He/NeBeta beam scenarios: He/Ne ““Low” gamma (Low” gamma (<150?)<150?)

- Alternative to superbeam? Originally designed for CERN (SPS)Alternative to superbeam? Originally designed for CERN (SPS)- Water Cherenkov detectorWater Cherenkov detector(see last slide; also: Volpe, 2003)(see last slide; also: Volpe, 2003)

““Medium” gamma (150<Medium” gamma (150<<300-350?)<300-350?)- Alternative to superbeam! Possible at upgraded SPS?Alternative to superbeam! Possible at upgraded SPS?- Usually: Water Cherenkov detectorUsually: Water Cherenkov detector(Burguet-Castell et al, 2003+2005; Huber et al, 2005; Donini, Fernandez-Martinez, 2006)(Burguet-Castell et al, 2003+2005; Huber et al, 2005; Donini, Fernandez-Martinez, 2006)

““High” gamma (300-350<High” gamma (300-350<<800?)<800?)- Specific physics case for that? Requires large accelerator (Tevatron-size)Specific physics case for that? Requires large accelerator (Tevatron-size)- Water Cherenkov detector or TASD or MID?Water Cherenkov detector or TASD or MID?(Burguet-Castell et al, 2003; Huber et al, 2005)(Burguet-Castell et al, 2003; Huber et al, 2005)

““Very high” gamma (Very high” gamma (>800?)>800?)- Alternative to neutrino factory? Requires very large accelerator (LHC-size)Alternative to neutrino factory? Requires very large accelerator (LHC-size)- Detector technology other than water (TASD? MID?)Detector technology other than water (TASD? MID?)(Burguet-Castell et al, 2003; Huber et al, 2005; Agarwalla et al, 2005+)(Burguet-Castell et al, 2003; Huber et al, 2005; Agarwalla et al, 2005+)

Gamma determines neutrino energyand therefore

detector technology!


Example: CERN-MemphysExample: CERN-Memphys(a superbeam-beta beam hybrid)(a superbeam-beta beam hybrid)

Beta beam (Beta beam (=100) plus=100) plus4MW superbeam to 440 kt4MW superbeam to 440 ktWC detector at Frejus WC detector at Frejus site (L=130 km)site (L=130 km)

Effect of systematics smaller Effect of systematics smaller and absolute performance and absolute performance better than for T2HKbetter than for T2HK

Antineutrino running not Antineutrino running not necessary because necessary because ee to to (beta beam) and (beta beam) and to to ee (superbeam) channels (superbeam) channels present present (see also: hep-ph/0703279)(see also: hep-ph/0703279) (Campagne, Maltoni, Mezzetto, Schwetz, 2006)(Campagne, Maltoni, Mezzetto, Schwetz, 2006)

10 years, 3Shading: systematics varied from 2% to 5%

Example: 13 discovery

Sensitive region


Example: Example: =350 optimum at CERN?=350 optimum at CERN? Requires refurbished SPS Requires refurbished SPS

(supercond. magnets)(supercond. magnets) Maximum doable at Maximum doable at

CERN?CERN? L=730 kmL=730 km For CPV an medium For CPV an medium 1313

even competitive to an even competitive to an optimized high-E NuFactoptimized high-E NuFact

(Burguet-Castell, Casper, Couce, (Burguet-Castell, Casper, Couce, Gomez-Cadenas, Hernandez, 2005; Fig. from Huber, Lindner, Rolinec, Winter, 2006)Gomez-Cadenas, Hernandez, 2005; Fig. from Huber, Lindner, Rolinec, Winter, 2006)

Green-field scenarioGreen-field scenario


Optimization of a green-field scenarioOptimization of a green-field scenario Use two different detector technologies:Use two different detector technologies:

– 500 kt Water Cherenkov: Large mass, but poor energy 500 kt Water Cherenkov: Large mass, but poor energy resolution at high E (non-QE sample)resolution at high E (non-QE sample)

– 50 kt NOvA-like TASD: Smaller mass, but very good energy 50 kt NOvA-like TASD: Smaller mass, but very good energy resolution at high Eresolution at high E

Assume specific isotopes: Assume specific isotopes: 66He, He, 1818Ne, Ne, with with 3 103 101818 ( (66He) and 10He) and 101818 ( (1818Ne) decays/yearNe) decays/year for 8 years for 8 years (if simultaneous operation)(if simultaneous operation)

Main questions (this talk): Main questions (this talk): – Which is the optimal gammaWhich is the optimal gamma– What is the optimal baseline?What is the optimal baseline?– Which fraction neutrinos/antineutrinos is necessary?Which fraction neutrinos/antineutrinos is necessary?


Scaling with Scaling with Fix L/Fix L/=1.3 (~ 1st oscillation maximum)=1.3 (~ 1st oscillation maximum)

The higher The higher , the better (modulo detector!), the better (modulo detector!)

(Huber, L

indner, Rolinec, W

inter, 2005)(H

uber, Lindner, R

olinec, Winter, 2005)

Our setups 1, 2, 3


Baseline optimization of a beta beamBaseline optimization of a beta beam Baseline optimization depends on performance indicatorBaseline optimization depends on performance indicator

and gamma setup:and gamma setup:

(Fig. from Huber, Lindner, Rolinec, Winter, 2005)(Fig. from Huber, Lindner, Rolinec, Winter, 2005)

For lower gamma: Second osc. max. useful to resolve degsFor lower gamma: Second osc. max. useful to resolve degs For higher gamma: Degs reolved by improved statistics For higher gamma: Degs reolved by improved statistics


Balance calculate as fraction of running time;Balance calculate as fraction of running time;translates easily into balance of useful isotope decays translates easily into balance of useful isotope decays

(Fig. from Huber, Lindner, Rolinec, Winter, 2005)(Fig. from Huber, Lindner, Rolinec, Winter, 2005)

Hardly imbalance as long as ~ 10% of the total running Hardly imbalance as long as ~ 10% of the total running time present (~ 10%/50%=20% of orig. isotope decays)time present (~ 10%/50%=20% of orig. isotope decays)

Neutrino-antineutrino balanceNeutrino-antineutrino balance


Comparison of setupsComparison of setups(H

uber, Lindner, R

olinec, Winter, 2005)

(Huber, L

indner, Rolinec, W

inter, 2005) 33

Using different isotopesUsing different isotopes


Isotopes compared: SpectrumIsotopes compared: Spectrum Example: Unoscillated spectrum for CERN-INO Example: Unoscillated spectrum for CERN-INO

Total flux ~ Total flux ~ NN 22 (forward boost!) (forward boost!) (N(N: useful ion decays): useful ion decays)

(from Agarwalla, Choubey, Raychaudhuri, 2006)

Peak E ~ E0 Max. E ~ 2 E0(E0 >> me assumed;

E0: endpoint energy)

(E0 ~ 14 MeV) (E0 ~ 4 MeV)


Examples for isotopesExamples for isotopes Want same neutrino energiesWant same neutrino energies

(=same X-sections, L, (=same X-sections, L, physicsphysics):):Peak energy ~ Peak energy ~ E E00, flux ~ , flux ~ NN 22

Use high Use high and isotopes with small E and isotopes with small E00 oror low low and isotopes with large E and isotopes with large E0 0

for same total fluxfor same total flux(exact for m(exact for mee/E/E0 0 << 1)<< 1)

Example (table): NExample (table): N(B/Li)(B/Li) ~ 12 N ~ 12 N

(He/Ne)(He/Ne) , , (He/Ne)(He/Ne) ~ 3.5 ~ 3.5 (B/Li)(B/Li) NB: NB: : : Accelerator dofAccelerator dof versus N versus N: : ion source dofion source dof

Where is the cost/feasibility break-even point?Where is the cost/feasibility break-even point?

Different isotopes: Some thoughtsDifferent isotopes: Some thoughts

(http://ie.lbl.gov/toi)


L-L--optimization for MID: -optimization for MID: 1313 sensitivity sensitivity

Same Same luminosity, luminosity, same detector!same detector!

Short baseline Short baseline better for better for He/Ne,He/Ne,magic baseline magic baseline for B/Li for B/Li

(in prep. with (in prep. with Agarwalla et al)Agarwalla et al)


A matter of luminosity? A matter of luminosity? Short vs. long baselineShort vs. long baselineG

amm

a in

crea

se: ~

2.9

-4.6

Same physics for ~ 10 x luminosity

(Agarw

alla, Choubey, R

aydchaudhuri, Winter, in prep.)

(Agarw

alla, Choubey, R

aydchaudhuri, Winter, in prep.)


Even use alternating ions?Even use alternating ions? Alternating ionsAlternating ions

possible degeneracypossible degeneracyresolution strategyresolution strategyIdeaIdea: main statistics: main statisticsat very differentat very differentneutrino energies!neutrino energies!

(Donini, Fernandez-Martinez, (Donini, Fernandez-Martinez, 2006)2006)

(for other degeneracy studies: see, e.g. Donini, Fernandez-Martinez, Rigolin, 2004; (for other degeneracy studies: see, e.g. Donini, Fernandez-Martinez, Rigolin, 2004; Donini, Fernandez-Martinez, Migliozzi, Rigolin, 2004)Donini, Fernandez-Martinez, Migliozzi, Rigolin, 2004)

L=650 km

Physics casePhysics case


Discussion: Physics case for a beta beam?Discussion: Physics case for a beta beam? Can do Can do 1313, mass hierarchy, CPV measurements just as superbeam, , mass hierarchy, CPV measurements just as superbeam,

neutrino factory; physics, in principle, similarneutrino factory; physics, in principle, similar Cannot:Cannot:

– Measure leading atm. parameters very wellMeasure leading atm. parameters very well– Be used for muon physics (such as a NF frontend!)Be used for muon physics (such as a NF frontend!)– Be used as a muon collider frontend (NF?)Be used as a muon collider frontend (NF?)– Be used for muon neutrino X-section measurementBe used for muon neutrino X-section measurement

Key questions:Key questions:– Synergies with other non-oscillation measurements?Synergies with other non-oscillation measurements?– Cost/useful ion decays (BB) versus cost/useful muon decays (NF)? How do Cost/useful ion decays (BB) versus cost/useful muon decays (NF)? How do

BB compare to superbeams?BB compare to superbeams?– Different isotopes versus different Different isotopes versus different ??– Potential for non-standard physics?Potential for non-standard physics?– Is there a seperate physics case for a beta beam?Is there a seperate physics case for a beta beam?


Separate physics case for a beta beam?Separate physics case for a beta beam?

Blue: Superbeam upgrade based upon: lower effortBlue: Superbeam upgrade based upon: lower effort Green: Beta beam based upon: Good CPV reach, MH in most casesGreen: Beta beam based upon: Good CPV reach, MH in most cases Red: Neutrino factory (optimized) based upon: Good Red: Neutrino factory (optimized) based upon: Good 1313 reach reach

(3m312=0.0022 eV2

Lon

ger

L


SummarySummary Beta beam performance depends on isotope and Beta beam performance depends on isotope and

, which determine the physics reaches, which determine the physics reaches The physics potential can be made similar to that The physics potential can be made similar to that

of a NF or SB; therefore, for standard oscillation of a NF or SB; therefore, for standard oscillation physics, it all comes down to a cost comparisonphysics, it all comes down to a cost comparisonHoweverHowever: there might be a separate physics case: there might be a separate physics casefor intermediate sinfor intermediate sin22221313

Isotope comparison master formulae:Isotope comparison master formulae: E E00

(1)(1) = = E E00(2)(2) , N , N

(1)(1)=N=N(2)(2) (E (E00

(1)(1)/E/E00(2)(2)))22

Accelerator effort versus ion source effortAccelerator effort versus ion source effort


Beta beam vs. Superbeam vs. NuFact?Beta beam vs. Superbeam vs. NuFact? LowerLower::

Can easily compete Can easily compete with superbeam with superbeam upgrades if properly upgrades if properly optimizedoptimized

Higher Higher ::At least theoretically At least theoretically competitive to a competitive to a neutrino factoryneutrino factory

Challenges:Challenges:- Can fluxes be reached?Can fluxes be reached?- Compare completely Compare completely

optimized accelerator optimized accelerator strategies?strategies?

(Fig. from Huber, Lindner, Rolinec, Winter, 2005)

Beta beam scenarios … for neutrino oscillation physics

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